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Climate engineering

From Wikipedia, the free encyclopedia
"Geoengineering" redirects here. For other uses, see Geoengineering (disambiguation).
Not to be confused with Weather modification.

Climate engineering (also known as geoengineering or climate intervention) is the deliberate large-scale interventions in the Earth’s climate system intended to counteract human-caused climate change.[1] The term commonly encompasses two broad categories: large-scale carbon dioxide removal (CDR) and solar radiation modification (SRM). CDR involves techniques to remove carbon dioxide from the atmosphere and is generally considered a form of climate change mitigation. SRM aims to reduce global warming by reflecting a small portion of sunlight (solar radiation) away from Earth and back into space. Although historically grouped together, these approaches differ substantially in mechanisms, timelines, and risk profiles, and are now typically discussed separately.[2]: 168 [3] Some other large-scale engineering proposals—such as interventions to slow the melting of polar and alpine ice—are also sometimes classified as forms of geoengineering.

Some types of climate engineering present political, social and ethical issues. One common objection is that focusing on these technologies could undermine efforts to reduce greenhouse gas emissions. Effective governance and international oversight are widely regarded as essential.

Major scientific organizations have examined the potential, risks, and governance needs of climate engineering, including the US National Academies of Sciences, Engineering, and Medicine,[4][5][6] the Royal Society,[7] the UN Educational, Scientific and Cultural Organization (UNESCO)[8], and the World Climate Research Programme.[1]

Methods

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Carbon dioxide removal

[edit]
This section is an excerpt from Carbon dioxide removal.[edit]
Planting trees is a nature-based way to remove carbon dioxide from the atmosphere; however, the effect may only be temporary in some cases.[9][10]

Carbon dioxide removal (CDR) is a process in which carbon dioxide (CO2) is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products.[11]: 2221  This process is also known as carbon removal, greenhouse gas removal or negative emissions. CDR is more and more often integrated into climate policy, as an element of climate change mitigation strategies.[12][13] Achieving net zero emissions will require first and foremost deep and sustained cuts in emissions, and then—in addition—the use of CDR ("CDR is what puts the net into net zero emissions" [14]). In the future, CDR may be able to counterbalance emissions that are technically difficult to eliminate, such as some agricultural and industrial emissions.[15]: 114 

CDR includes methods that are implemented on land or in aquatic systems. Land-based methods include afforestation, reforestation, agricultural practices that sequester carbon in soils (carbon farming), bioenergy with carbon capture and storage (BECCS), and direct air capture combined with storage.[15][16] There are also CDR methods that use oceans and other water bodies. Those are called ocean fertilization, ocean alkalinity enhancement,[17] wetland restoration and blue carbon approaches.[15] A detailed analysis needs to be performed to assess how much negative emissions a particular process achieves. This analysis includes life cycle analysis and "monitoring, reporting, and verification" (MRV) of the entire process.[18] Carbon capture and storage (CCS) are not regarded as CDR because CCS does not reduce the amount of carbon dioxide already in the atmosphere.

Solar radiation modification

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refer to caption and image description
Proposed solar radiation modification using a tethered balloon to inject sulfate aerosols into the stratosphere
This section is an excerpt from Solar radiation modification.[edit]
Not to be confused with weather modification.

Solar radiation modification (SRM) (or solar geoengineering or solar radiation management), is a group of large-scale approaches to reduce global warming by increasing the amount of sunlight (solar radiation) that is reflected away from Earth and back to space. Among the potential methods, stratospheric aerosol injection (SAI) is the most-studied,[19]: 350  followed by marine cloud brightening (MCB); others such as ground- and space-based methods show less potential or feasibility and receive less attention. SRM could be a supplement to climate change mitigation and adaptation measures,[20]: 1489  but would not be a substitute for reducing greenhouse gas emissions.[21] SRM is a form of climate engineering or geoengineering, and might be able to prevent some kinds of tipping.[22]

Scientific studies, based on evidence from climate models, have consistently shown that SRM could reduce global warming and many effects of climate change.[23][24][25] However, because warming from greenhouse gases and cooling from SRM would operate differently across latitudes and seasons, a world where global warming would be reduced by SRM would have a different climate from one where this warming did not occur in the first place. SRM would therefore pose environmental risks, as would a warmed world without SRM. Confidence in the current projections of how SRM would affect regional climate and ecosystems is low.[20]: 1491–1492 

Glacial geoengineering

[edit]
This section is an excerpt from Glacial geoengineering.[edit]
Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979-2000 average

Glacial geoengineering is a set of proposed geoengineering that focus on slowing the loss of glaciers, ice sheets, and sea ice in polar regions and, in some cases, alpine areas. Proposals are motivated by concerns that feedback loops—such as ice-albedo loss, accelerated glacier flow, and permafrost methane release—could amplify climate change and trigger climate tipping points.[26][27]

Proposed glacial geoengineering methods include regional or local solar radiation management, thinning cirrus clouds to allow more heat to escape, and deploying mechanical or engineering structures to stabilize ice. Specific strategies under investigation are stratospheric aerosol injection focused on polar regions,[26] marine cloud brightening,[28] surface albedo modification with reflective materials,[29] basal interventions such as draining subglacial water or promoting basal freezing,[27] and ice shelf protection measures including seabed curtains.[30]

Glacial geoengineering is in the early research stage and many proposals face major technical, environmental, and governance challenges.[28] Supporters argue that targeted interventions could help stabilize ice sheets, slow sea-level rise, and reduce the risk of passing irreversible thresholds in the climate system. At the same time, experts caution that the effectiveness of these methods remains highly uncertain and that interventions could produce unintended side effects.[27] Glacial geoengineering is generally considered a possible complement to, not a replacement for, efforts to reduce greenhouse gas emissions.[26][28]

Governance

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Most governance issues relating geoengineering are specific to the category or the specific method. Nevertheless, a couple of international governance instruments have addressed geoengineering collectively.

The Conference of Parties to the Convention on Biological Diversity have made several decisions regarding "climate related geoengineering." That of 2010 established "a comprehensive non-binding normative framework"[31]: 106  for "climate-related geoengineering activities that may affect biodiversity," requesting that such activities be justified by the need to gather specific scientific data, undergo prior environmental assessment, be subject to effective regulatory oversight.[32]: 96–97 [33]: 161–162  The Parties' 2016 decision called for "more transdisciplinary research and sharing of knowledge... in order to better understand the impacts of climate-related geoengineering."[33]: 161-162 [34]

The parties to the London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter and its associated London Protocol have addressed "marine geoengineering." In 2013, the parties to the London Protocol adopted an amendment to establish a legally binding framework for regulating marine geoengineering, initially limited to ocean fertilization and requiring assessment and permitting before any activity proceeds. This amendment has not yet entered into force due to insufficient ratifications. In 2022, the parties to both agreements acknowledged growing interest in marine geoengineering, identified four techniques for priority review, and encouraged careful assessment of proposed projects under existing guidelines while considering options for further regulation. In 2023, they cautioned that these techniques could pose serious environmental risks, highlighted scientific uncertainty about their effects, urged strict application of assessment frameworks, and called for broader international cooperation.[35] Their work is supported by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection of the International Maritime Organization.

References

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  1. ^ a b World Climate Research Programme. "Research on Climate Intervention". www.wcrp-climate.org.
  2. ^ IPCC (2022) Chapter 1: Introduction and Framing in Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA
  3. ^ IPCC, 2021: Annex VII: Glossary [Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C.  Méndez, S. Semenov, A. Reisinger (eds.)]. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, doi:10.1017/9781009157896.022.
  4. ^ Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base. Washington, D.C.: National Academies Press. 1992-01-01. doi:10.17226/1605. ISBN 978-0-309-04386-1.
  5. ^ Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration. Washington, D.C.: National Academies Press. 2015-06-17. doi:10.17226/18805. ISBN 978-0-309-30529-7.
  6. ^ Climate Intervention: Reflecting Sunlight to Cool Earth. Washington, D.C.: National Academies Press. 2015-06-23. doi:10.17226/18988. ISBN 978-0-309-31482-4.
  7. ^ Royal Society of London, ed. (2009). Geoengineering the climate: Science, governance and uncertainty. London. ISBN 978-0-85403-773-5.{{cite book}}: CS1 maint: location missing publisher (link)
  8. ^ UNESCO World Commission on the Ethics of Scientific Knowledge and Technology (2023). "Report of the World Commission on the Ethics of Scientific Knowledge and Technology (COMEST) on the ethics of climate engineering". Retrieved 2024-03-09.
  9. ^ Buis, Alan (November 7, 2019). "Examining the Viability of Planting Trees to Help Mitigate Climate Change". Climate Change: Vital Signs of the Planet. Retrieved 2023-04-13.
  10. ^ Marshall, Michael (26 May 2020). "Planting trees doesn't always help with climate change". BBC. Retrieved 2023-04-13.
  11. ^ IPCC, 2021: "Annex VII: Glossary". Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C. Méndez, S. Semenov, A. Reisinger (eds.). In "Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change". Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, doi:10.1017/9781009157896.022
  12. ^ Schenuit, Felix; Colvin, Rebecca; Fridahl, Mathias; McMullin, Barry; Reisinger, Andy; Sanchez, Daniel L.; Smith, Stephen M.; Torvanger, Asbjørn; Wreford, Anita; Geden, Oliver (2021-03-04). "Carbon Dioxide Removal Policy in the Making: Assessing Developments in 9 OECD Cases". Frontiers in Climate. 3: 638805. doi:10.3389/fclim.2021.638805. hdl:1885/270309. ISSN 2624-9553.
  13. ^ Geden, Oliver (May 2016). "An actionable climate target". Nature Geoscience. 9 (5): 340–342. Bibcode:2016NatGe...9..340G. doi:10.1038/ngeo2699. ISSN 1752-0908. Archived from the original on May 25, 2021. Retrieved March 7, 2021.
  14. ^ Ho, David T. (2023-04-04). "Carbon dioxide removal is not a current climate solution — we need to change the narrative". Nature. 616 (7955): 9. Bibcode:2023Natur.616....9H. doi:10.1038/d41586-023-00953-x. ISSN 0028-0836. PMID 37016122. S2CID 257915220.
  15. ^ a b c M. Pathak, R. Slade, P.R. Shukla, J. Skea, R. Pichs-Madruga, D. Ürge-Vorsatz,2022: Technical Summary. In: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.002.
  16. ^ Rackley, Steve; Andrews, Graham; Clery, Diarmaid; De Richter, Renaud; Dowson, George; Knops, Pol; Li, We; Mccord, Stephen; Ming, Tingzhen; Sewel, Adrienne; Styring, Peter; Tyka, Michael (2023). Negative Emissions Technologies for Climate Change Mitigation. Elsevier. ISBN 978-0-12-819663-2.
  17. ^ Lebling, Katie; Northrop, Eliza; McCormick, Colin; Bridgwater, Liz (November 15, 2022), "Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal: Research and Governance Priorities" (PDF), World Resources Institute: 11, doi:10.46830/wrirpt.21.00090, S2CID 253561039
  18. ^ Schenuit, Felix; Gidden, Matthew J.; Boettcher, Miranda; Brutschin, Elina; Fyson, Claire; Gasser, Thomas; Geden, Oliver; Lamb, William F.; Mace, M. J.; Minx, Jan; Riahi, Keywan (2023-10-03). "Secure robust carbon dioxide removal policy through credible certification". Communications Earth & Environment. 4 (1): 349. Bibcode:2023ComEE...4..349S. doi:10.1038/s43247-023-01014-x. ISSN 2662-4435.
  19. ^ Ipcc (2022-06-09). Global Warming of 1.5°C: IPCC Special Report on Impacts of Global Warming of 1.5°C above Pre-industrial Levels in Context of Strengthening Response to Climate Change, Sustainable Development, and Efforts to Eradicate Poverty (1 ed.). Cambridge University Press. doi:10.1017/9781009157940.006. ISBN 978-1-009-15794-0.
  20. ^ a b Intergovernmental Panel on Climate Change (2021). Climate Change 2021: Mitigation of Climate Change – Working Group III Contribution.
  21. ^ Helwegen, Koen G.; Wieners, Claudia E.; Frank, Jason E.; Dijkstra, Henk A. (2019-07-15). "Complementing CO2 emission reduction by solar radiation management might strongly enhance future welfare". Earth System Dynamics. 10 (3): 453–472. doi:10.5194/esd-10-453-2019. ISSN 2190-4979. even if successful, SRM can not replace but only complement CO2 abatement.
  22. ^ Futerman, Gideon; Adhikari, Mira; Duffey, Alistair; Fan, Yuanchao; Irvine, Peter; Gurevitch, Jessica; Wieners, Claudia (2023-10-10). "The interaction of Solar Radiation Modification and Earth System Tipping Elements". EGUsphere: 1–70. doi:10.5194/egusphere-2023-1753.
  23. ^ Intergovernmental Panel on Climate Change (2021). Climate Change 2021: The Physical Science Basis – Working Group I Contribution to the Sixth Assessment Report of the IPCC. Cambridge University Press.
  24. ^ "One Atmosphere: An Independent Expert Review on Solar Radiation Modification Research and Deployment". UN Environment Programme. 2023. Retrieved 2024-03-09.
  25. ^ World Meteorological Organization (2022). Scientific Assessment of Ozone Depletion 2022. World Meteorological Organization.
  26. ^ a b c Duffey, Alistair; Irvine, Peter; Tsamados, Michel; Stroeve, Julienne (31 May 2023). "Solar Geoengineering in the Polar Regions: A Review". Earth's Future. 11 (6). doi:10.1029/2023EF003679. ISSN 2328-4277.
  27. ^ a b c Minunno, R.; Andersson, N.; Morrison, G.M. (18 April 2023). "A systematic literature review considering the implementation of planetary geoengineering techniques for the mitigation of sea-level rise". Earth-Science Reviews. 241: 104431. doi:10.1016/j.earscirev.2023.104431.
  28. ^ a b c Wang, Feiteng; Xie, Yida; Wang, Lin; Liu, Shuangshuang; Jin, Xiang (15 January 2025). "Mitigating ice sheets and mountain glaciers melt with geoengineering". Science of The Total Environment. 963: 178450. doi:10.1016/j.scitotenv.2025.178450.
  29. ^ "Thawing Permafrost Could Leach Microbes, Chemicals Into Environment". Jet Propulsion Laboratory. 9 March 2022.
  30. ^ Gertner, Jon (2024-01-06). "Can $500 Million Save This Glacier?". The New York Times. ISSN 0362-4331. Archived from the original on 9 Jan 2024. Retrieved 2025-04-27.
  31. ^ Geoengineering in relation to the Convention on Biological Diversity. CBD technical series. Montreal: Secretariat of the Convention on Biological Diversity. 2012. ISBN 978-92-9225-429-2.
  32. ^ National Academies of Sciences, Engineering (2021-03-25). Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance. doi:10.17226/25762. ISBN 978-0-309-67605-2. Archived from the original on 2021-04-17. Retrieved 2021-04-17.
  33. ^ a b Scientific Advice Mechanism to the European Commission (2024-12-09). Solar radiation modification: evidence review report (Report). SAPEA. doi:10.5281/zenodo.14283096.
  34. ^ Convention on Biological Diversity, Conference of the Parties to the (8 December 2016). Decision Adopted by the Conference of the Parties to the Convention on Biological Diversity, XIII/14. Climate-related Geoengineering (PDF).{{cite book}}: CS1 maint: date and year (link)
  35. ^ International Maritime Organization. "Marine geoengineering".
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